Importance of Beta blocker in IHD

🔴 Topic : Beta blocker in IHD Beta-blockers are often indicated even when the heart rate (HR) is already relatively low in patients with ischemic heart disease (IHD), but only within safe limits. The decision is based on balancing their proven benefits against the risk of excessive bradycardia. 🔴 Why give a beta-blocker in IHD? Beta-blockers have several important benefits: 📌 Reduce myocardial oxygen demand ↓ Heart rate ↓ Myocardial contractility ↓ Blood pressure ↓ Wall stress 📌 Prolong diastole 📌 Coronary perfusion occurs mainly during diastole. 📌 A slightly slower HR allows more time for coronary blood flow, which is particularly beneficial in IHD. 📌 Reduce ventricular arrhythmias Important after myocardial infarction. 📌 Prevent adverse ventricular remodeling specially after STEMI/NSTEMI with reduced LVEF. This benefit is mediated by blocking chronic sympathetic activation. 🔴 How low is "too low"? This is where clinical judgment is important. 🔴 Resting HR ≥60 bpm 📌 Generally safe to start a beta-blocker if there are no contraindications. 📌 Start with a low dose and titrate gradually. 🔴 HR 50-60 bpm May still prescribe if: 📌 Patient is asymptomatic. 📌 Blood pressure is adequate. 📌 There is a strong indication (recent MI, HFrEF, angina). 📌 Start at a very low dose and monitor. 🔴 HR <50 bpm 📌 Usually avoid initiating beta-blockers unless there is a compelling reason and specialist supervision. 📌 Evaluate causes of bradycardia first. 🔴 Contraindications or situations to avoid 📌 Do not start or increase beta-blockers in patients with: - Symptomatic bradycardia - HR <50 bpm - Second- or third-degree AV block (without a pacemaker) - Sick sinus syndrome - Cardiogenic shock - Acute decompensated heart failure 🔴 After Myocardial Infarction Patients with: 📌 MI + LVEF ≤40% 📌 Heart failure 📌 Anterior MI derive the greatest survival benefit from beta-blockers, even if the resting HR is around 55-60 bpm, provided they are hemodynamically stable. 🔴 Stable Chronic Coronary Syndrome 📌 For chronic stable angina: - Beta-blockers are first-line antianginal drugs. - The target resting HR is approximately 55-60 bpm if tolerated. 📌 If HR is already below this, clinicians may choose another anti-anginal agent, such as: - Long-acting nitrates - Ranolazine rather than further lowering the HR. Dr. Muhammad Mosleh Uddin MBBS (CMC), FCPS trainee (Cardiology) www.drmoslehuddin.com